Evaluation of HIF1A expression level and parenchymal-stromal relationships after traumatic air shock wave exposure to the liver

The purpose of the study was to investigate, analyze and evaluate the expression level of HIF1A and parenchymal-stromal relations after traumatic air shock wave exposure to the liver. 
Materials and methods. The material for the study was the liver of 30 male rats, weighing 177.5 ± 15.8 g. All animals were randomly divided into three groups: group 1 consisted of intact rats (n - 6), group 2 – control (halothane anesthesia with fixation) (n - 12), group 3 (n - 12) – experimental animals (halothane anesthesia with fixation, traumatic single action of an air shock wave with an excess pressure of 31.6 ± 4.8, which was generated in the device developed by us). In order to study the reactive changes in the liver after exposure to an air shock wave, an immunohistochemical method was used to study the expression of the hypoxia marker HIF1A and a morphometric analysis of parenchymal-stromal relations on the 7th and 30th day of the  experiment. 
Results and discussion. The studied expression of the transcription factor HIF1A in the liver after exposure to an air shock wave by the immunohistochemical method showed a relationship with the consequences that occur after the injury (alteration, inflammation, regeneration), as well as with the observation period and distribution in the liver parenchyma. Despite the diffuse injury of the liver, which occurs after a low-intensity exposure to an air shock wave, we record a high threshold of resistance of liver cells to the action of this traumatic factor. The absence of HIF1A expression in the liver one month after exposure to an air shock wave is a direct indication of the restoration of the functioning of specialized liver cells, despite the initial significant diffuse changes at the level of the microcirculatory channel of the liver lobules. Research has repeatedly shown the high regenerative potential of the liver, despite the factors of influence, toxic, mechanical,  and others.
Understanding the spatial response of liver cells to external and internal factors will allow us to assess the adaptive capabilities of the metabolism of hepatocytes that are in different conditions of blood supply, which will expand our knowledge about the pathogenesis of the post-traumatic period and offer new therapeutic tools for their correction.
Conclusion. Morphometric analysis of parenchymal-stromal relations of the liver after a single exposure to an air shock wave showed a significant decrease in the area of hepatocytes  by 8% and a significant increase in the area of connective  tissue by almost 2.4 times on the 30th day of the post-traumatic period in comparison with the control group of animals. Evaluation of the level of expression of the transcription factor HIF1A in the liver at the stages of the post-traumatic period showed that moderate expression was characteristic of the subcapsular area of  the liver in the early post-traumatic period. On the 30th day of the post-traumatic period, the accumulation of the HIF1A marker in the liver of the experimental group of animals was not statistically significant compared to the control group.